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TS5A9411: Interfacing Questions

Part Number: TS5A9411
Other Parts Discussed in Thread: TS12A12511, TLV171

Hi,

I have a couple of voltage and current interfacing questions regarding the  TS5A9411:

1) Is this switch suitable for switching a signal to a micro ADC?

2) With VCC (+5V) and GND (0V) can I supply COM, NO and NC DC voltages from -5V to +5V?

3) Can I drive the IN pin with the output of an LM393AD comparator.  The datasheet quotes the LM393AD can drive a max of 20mA.

3) Am I understanding the datasheet correctly and thinking NC, NO and COM can supply a maximum of 200mA?

Thanks,

Rocketman46

  • Rocketman46,

    1) Is this switch suitable for switching a signal to a micro ADC?

    Yes, you can use the TS5A9411 device to switch signals to a micro ADC if the voltages are within the recommended operating conditions.

    2) With VCC (+5V) and GND (0V) can I supply COM, NO and NC DC voltages from -5V to +5V?

    No, the minimum recommended voltage is 0 V.  You cannot pass -5V through the signal switch. 



    In order to support +/- 5V signals you will need to use a dual supply switch like the TS12A12511 device.

    3) Can I drive the IN pin with the output of an LM393AD comparator.  The datasheet quotes the LM393AD can drive a max of 20mA.

    The digital logic control pin (IN) is a high impedance input CMOS logic buffer and doesn't need a strong driver.  20mA would be plenty to control the IN pin of the signal switch. 

    Are you not able to get the TS5A9411 device to change states with the LM393AD comparator?  Do you have a diagram of your circuit?  Are you including a pull up resistor for the logic high level?

    3) Am I understanding the datasheet correctly and thinking NC, NO and COM can supply a maximum of 200mA?

    No, The TS5A9411 is a passive FET switch and will not provide any current.  This device will simply pass the signal from one side of the switch to the other without any additional drive current. 

    What are you attempting to accomplish?  Do you have a diagram of your circuit? 

    Thank you,

    Adam

  • Hi Adam,

    Thanks for your reply.

    I am essential splinting -5V to +5V into two voltages, (-5V to -0.25V) and (+0.25V to +5V), i have done this with the LM393AD comparators.  This circuit is a left, right and neutral control for a joystick.

    I am unsure if the outputs of the LM393AD comparators with turn Q1,  Q2 FETs on and switch the relay.  I have considered replacing Q1, Q2, K1 and K2 with an analogue switch like the TS12A12511.

    So to conclude, will the comparator outputs drive the FETS, or would it be better to use the TS12A12511.  Also is the TLV171IDR opamp a good choice for this application?

    An tips kindly accepted as I am a little unsure on my circuit.

    Thanks,

    Rocketman46

  • Rocketman46,

    From my understanding it looks like you are taking a signal from the -5V to +5V voltage IN node and making a choice on what to communicate to Micron ADC 0-5V OUT node.  On the Micron ADC 0-5V OUT node there can either be two signals from NO pin of TS59411 the output of TLV171IDR or from NC pin the voltage from -5V to +5V node based on the status of the control logic of the TS5A9411 (IN pin). 

    If the voltage on -5V to 5V voltage IN node is > 0.25 than U1A1 will pull low connecting NC and COM of the TS5A9411 and connect the relay to pass the >0.25 voltage through to Micron ADC 0-5V OUT.

    If the voltage on -5V to 5V voltage IN node is < -0.25 than U1A1 will Hi-Z connecting NO and COM of the TS5A9411 and connect the relay to pass the < -0.25 voltage through to Micron ADC 0-5V OUT through the TLV171 amplifier.

    This situation above will not be valid for the TS5A9411 devices because -5V on the NO pin is outside the recommended operating conditions of the switch.

    If you use the TS12A12511 and with positive supply at 5V and negative supply a -5V it will be able to support this circuit.

    I'm going to have people from the op amp team comment on the amplifier.

    Thank you,

    Adam

      

  • Hi Rocketman,

    It looks like you're using the TLV171 as an inverting amplifier for your design. This device will work in this configuration but if you can provide more information on desired performance, we'll be able to look and see if there is a better device. But right now I don't see any issues.

    -Paul
  • Hi Adam,

    Thanks for your reply.

    From my understanding it looks like you are taking a signal from the -5V to +5V voltage IN node and making a choice on what to communicate to Micron ADC 0-5V OUT node.  On the Micron ADC 0-5V OUT node there can either be two signals from NO pin of TS59411 the output of TLV171IDR or from NC pin the voltage from -5V to +5V node based on the status of the control logic of the TS5A9411 (IN pin). 
    
    If the voltage on -5V to 5V voltage IN node is > 0.25 than U1A1 will pull low connecting NC and COM of the TS5A9411 and connect the relay to pass the >0.25 voltage through to Micron ADC 0-5V OUT.
    
    If the voltage on -5V to 5V voltage IN node is < -0.25 than U1A1 will Hi-Z connecting NO and COM of the TS5A9411 and connect the relay to pass the < -0.25 voltage through to Micron ADC 0-5V OUT through the TLV171 amplifier.
    
    This situation above will not be valid for the TS5A9411 devices because -5V on the NO pin is outside the recommended operating conditions of the switch.

    As I understand, the -025V to -5V signal is going through an inverting op-amp U2 after the K2 relay, and therefore the TS5A9411 NO pin will not see a negative voltage. It will see a second +0.25V to +5V? Is this correct or is my design wrong? If you use the TS12A12511 and with positive supply at 5V and negative supply a -5V it will be able to support this circuit. I'm going to have people from the op amp team comment on the amplifier. Thank you, Rocketman46

  • Hi Adam,

    As I understand, the -025V to -5V signal is going through an inverting op-amp U2 after the K2 relay, and therefore the TS5A9411 NO pin will not see a negative voltage. It will see a second +0.25V to +5V?

    Is this correct or is my design wrong?

    Thanks,

    Rocketman46
  • Rocketmann,

    That was an oversight on my part. You may use the TS5A9411 if the device doesn't see a negative voltage on the signal path.

    Thank you,
    Adam